tree 5c0e775ba46d64393d1d2aff3f5165bc66ce298e
parent 535c50f9c0e5187e2e7bbbe318d5d4260125835a
author sewardj <sewardj@a5019735-40e9-0310-863c-91ae7b9d1cf9> 1118174696 +0000
committer sewardj <sewardj@a5019735-40e9-0310-863c-91ae7b9d1cf9> 1118174696 +0000


A major overhaul of all machinery to do with syscalls, but mostly of
the m_syscalls module.  Fundamentally the aim of the overhaul is to
clean up the logic and abstractions surrounding syscalls in order that
we can cleanly support ppc32 and other new targets.  Aims in detail:

* To further decouple the syscall PRE/POST wrappers from specifics of
  how those values are stored on a given platform.  The wrappers look
  the same as they did before, mostly (eg, references to ARGn and
  RES are unchanged), but now those macros refer to values in structs
  SyscallArgs and SyscallStatus (see priv_types_n_macros.h).

* Complete overhaul of the driver logic for syscalls.  The resulting
  logic is algorithmically identical to what we had before, but is
  more documented, and deals with moving arg/result data between
  platform specific representations and the canonical forms in
  structs SyscallArgs and SyscallStatus.

* Also as a result of this change, remove problems in the old logic
  due to assignments of RES in PRE wrappers trashing the ARGs whilst
  we still need to see them.

* Lots of other cleanups and documentation.  There is extensive
  commentary in syscalls-main.c.

The driver logic has been placed in its own file, syscalls-main.c.

New/deleted files in m_syscalls:

* syscalls.c is divided up into syscalls-main.c, containing driver
  logic, and syscalls-generic.c, containing generic Unix wrappers.

* priv_syscalls.h is chopped up into priv_types_n_macros.h
  and priv_syscalls-{generic,main}.h.

                           ------------

All the above changes are in m_syscalls.  However there is one
system-wide change as a result of all this.

The x86-linux assumption that syscall return values in the range -4095
.. -1 are errors and all others are values, has been done away with
everywhere.  Instead there is a new basic type SysRes which holds a
system call result in a platform-neutral way.

Everywhere that previously an Int would have held a system call
result, there is now a SysRes in its place.

                           ------------

Almost everything works on SuSE 9.1 (LinuxThreads) again.  NPTL will
still be majorly broken; I will commit fixes shortly.  AMD64 is also
totalled.  I will get to that too.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@3849 a5019735-40e9-0310-863c-91ae7b9d1cf9